Technical and medical endoscopes are delicate optical instruments that are introduced into technical and human cavities for inspecting the interiors of such cavities. Endoscopes can be rigid endoscopes containing a lens system, flexible endoscopes containing a flexible image guiding bundle or video endoscopes. These endoscopes have a small diameter of a few millimeters but are often several hundreds of millimeter long.
Endoscopes generally comprise an outer tube and an inner tube. The space between the outer tube and the inner tube is filled with illumination fibers which guide externally created light inside of the cavities being inspected. Rigid endoscopes have inside the inner tube an optical system that relays images of a cavity from the distal tip of the endoscope back to the proximal end of the endoscope. This relayed image can be observed at the proximal end by the operator's eye, or a video camera can capture the image.
In use, rigid endoscopes are inserted along an insertion tube which cannot freely move in the body cavity. Thus, to look at a direction adjacent to the insertion direction of a rigid endoscope, the rigid endoscope often includes a deflecting prism at the distal tip of the optical system. In flexible endoscopes the image is relayed by a fiber image bundle to the ocular at the proximal end of the endoscope. Video endoscopes have a chip built into the distal tip of the endoscope that delivers the image in electronic form directly to an external video controller.
Because of their extreme physical dimensions, endoscopes are often stressed during cleaning, sterilization and usage. These stresses can cause bending of the instruments, or chipping, breaking or dislocating of the glass lenses or the deflection prisms. Further, the illumination fibers can break, debris can accumulate on the end of the fiber illumination bundle or on the windows enclosing the optical system, and fluid can enter the optical system of the instruments during cleaning or sterilization. Therefore, endoscopes are often damaged and their performance degraded to an extent where the safe usage of the instruments is no longer warranted. When this occurs, the damaged endoscopes must be separated form the inventory and properly cleaned or sent out to a service company for internal cleaning or repair. However, if a damaged endoscope is not detected prior to a planned surgery, the medical procedure can be delayed, canceled or the outcome of the procedure can be compromised.
In the patent literature various test equipment for endoscopes is described. For example, U.S. Pat. No. 6,203,492 and U.S. Pat. No. 6,673,011 describe pieces of equipment that hold and protect endoscopes when the pupil of the endoscopes are scanned for damage and debris. This equipment is easy to use but does not give a clear determination if the equipment is ready for use or not. The endoscope testing equipment described in U.S. Pat. Nos. 4,613,232, 5,966,210 and 6,498,642 use time consuming procedures to collect data that require technical knowledge and skills and checking of the data against a manufacturer's specification and tolerances. Further, U.S. Pat. No. 6,069,691 and U.S. Pat. No. 7,022,065 describe test equipment for endoscopes that is automated or computer controlled. This makes the equipment easier to handle, but the equipment is more expensive and delicate.